Add sample for iothub with private link

quickstart/201-private-link-iothub-builtin-endpoint/main.tf

@@ -0,0 +1,65 @@
+resource "random_string" "suffix" {
+  length  = 5
+  special = false
+  upper   = false
+}
+
+resource "azurerm_resource_group" "rg" {
+  name     = "rg-iothub-${random_string.suffix.result}"
+  location = var.location
+}
+
+resource "azurerm_iothub" "iothub" {
+  name                = "iothub-${random_string.suffix.result}"
+  resource_group_name = azurerm_resource_group.rg.name
+  location            = azurerm_resource_group.rg.location
+  public_network_access_enabled = false
+
+  sku {
+    name     = "S1"
+    capacity = 1
+  }
+
+  cloud_to_device {
+    max_delivery_count = 30
+    default_ttl        = "PT1H"
+    feedback {
+      time_to_live       = "PT1H10M"
+      max_delivery_count = 15
+      lock_duration      = "PT30S"
+    }
+  }
+
+}
+
+resource "azurerm_iothub_shared_access_policy" "iothub_policy" {
+  name                = "iothub-policy"
+  resource_group_name = azurerm_resource_group.rg.name
+  iothub_name         = azurerm_iothub.iothub.name
+
+  registry_read   = true
+  registry_write  = true
+  service_connect = true
+
+  depends_on = [azurerm_private_endpoint.iothub]
+}
+
+resource "azurerm_iothub_dps" "dps" {
+  name                = "test-device-${random_string.suffix.result}"
+  resource_group_name = azurerm_resource_group.rg.name
+  location            = azurerm_resource_group.rg.location
+  allocation_policy   = "Hashed"
+  public_network_access_enabled = false
+
+  sku {
+    name     = "S1"
+    capacity = "1"
+  }
+
+  linked_hub {
+    connection_string = azurerm_iothub_shared_access_policy.iothub_policy.primary_connection_string
+    location = azurerm_resource_group.rg.location
+    allocation_weight       = 150
+    apply_allocation_policy = true
+  }
+}